I have a pile of incompatible wheels and tires - 1978 b7100 - expensive issue!!!!!!!

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
I decided to make a new post to hopefully get more attention and solve this issue.

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I bought a set of turf wheels and tires to have the tractor mobile while I swap out my R1 tires, and to also use once my lawn grows in (instead of the R1’s). Fronts are 20.5 and I think that’s the wrong size.

Second and the MAJOR issue. I ordered new 8-16 R1’s and new 6-12 R1’s. When they came in, they looked skinny, but being 8-16’s just like the ones on there, I thought maybe it’s just because they were new. Well after mounting, they are definitely WAY too skinny. Of course now they’re mounted so I probably can’t return. 🤦🏻‍♂️

so how to I fix this the least expensive way possible? I already emailed Tires Shipped 2 You to see wtf is going on with the size of the tire (and tread pattern… stamping on the side all looks correct, but the physical size is WAY different.

8C3EA158-74E3-440F-BA67-710282198DE9.jpeg


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I’m dead in the water until I get these R1’s sorted out.
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
Ok, Been doing a bunch more reading.

My rear R1 WHEELS are 16x8, and had 8-16's on them before.

My NEW R1 Tires are Carlisle Farm Specialist 8-16. Didn't know this before, but the specs sheet online specifies a 6 inch wheel. It also specifies a Section width of 8.3" (My measurement says 6.5")

So, IF the B7100 front-rear ratio is 1.4664, requiring a 0-5% lead... (Lets assume all Carlisle Farm Specialist tires here)

Using This Formula quoted below, and the manufacturer numbers here: https://www.carlislebrandtires.com/our-products/product-detail/farm-specialist-r1/

Rear - 29 x 12.50 x 15 (RC = 88 inch @ 15psi) Carlisle TRU POWER
Front - 20 x 8 x 10 (RC = 62 inch @ 25psi) Kenda K378


62 x 1.464 = 90.768 divided by 88 = 1.0314 minus 1 x 100 = 3.14 %

well within the 0-5% lead reccomended by Kubota
I come up with these numbers. Highlighted in green are the tires I ordered, based on other recommendations on this site.

But even the older part number 8-16 looks to have a 7.2% lead, while the newer 6X part number has a nearly 10% lead!

But if I get the 9.5-16 (meant for 8" wide rims) that has a 2.4% lead.

If all of the equations are correct in the quoted post above, AND the 1.4664 ratio is correct.

Screen Shot 2022-07-15 at 10.47.13 PM.png


Even 98.5/68.9 = 1.4296 (Very close to 1.4664)
And 92/68.9 = 1.3353 (Not close to 1.4664)

Does this sound correct?
 

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North Idaho Wolfman

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L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
23,164
1,263
113
Sandpoint, ID
Width is not an issue besides look, won't effect running at all.
The new tires are taller than the originals, but I bet the fronts are taller too.
With those two factors they will balance out.

If you did 9.5-16's you would need to go a larger size tire on the front and if my memory serves me right there is no good match.
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
Width is not an issue besides look, won't effect running at all.
The new tires are taller than the originals, but I bet the fronts are taller too.
With those two factors they will balance out.

If you did 9.5-16's you would need to go a larger size tire on the front and if my memory serves me right there is no good match.
So is my math above wrong then?

I also have 8” wide wheels. Not sure if that Becomes an issue for tires that were designed to go on 6 inch wide wheels.
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
Ok, my Carlisle Farm Specialist 9.5-16's came in!

Part Number 6x17413
Pairing with the original 6-12's I ordered (570030)

In the red "test rear" block is the off-rim MEASURED circumfrerence around the center of the tire,
In the red "test front" block is the listed rolling circumference. (I measured it off rim and it was just over 69")

So using the listed RC for the front and the off-rim measured circumference for the rear should give me the largest distance possible, and it's still got a front lead to it. (albeit, slight).

Going to mount these tires up and get them on the tractor now that I've confirmed this. Will report back.

Screen Shot 2022-07-23 at 6.54.05 AM.png
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
Well the 9.5-16 worked!!!! Just drove it up and down the street in 4x4 and no binding at all. Very easy to put it in and out of 4x4 at all times

LOOK AT THE TIRE DIFFERENCE! And the math worked out too, so I’m happy to see that it really did work.
6-12, 6-12, 8-16, 8-16, 9.5-16 on rim

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Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
3,872
1,523
113
North of Pittsburgh PA
Well the 9.5-16 worked!!!! Just drove it up and down the street in 4x4 and no binding at all. Very easy to put it in and out of 4x4 at all times

LOOK AT THE TIRE DIFFERENCE! And the math worked out too, so I’m happy to see that it really did work.
6-12, 6-12, 8-16, 8-16, 9.5-16 on rim

View attachment 84064

View attachment 84065
OK, I’m confused. it looks like the second tire from the left and the fifth tire from the left are the new tires.

But the second tire from the left is maybe just slightly smaller in diameter than the first tire. And the fifth tire from the left is larger than everything else. BUT the 2nd tire and the fifth tire seem to work perfectly. Is this an indication that the original tires were mismatche?
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
OK, I’m confused. it looks like the second tire from the left and the fifth tire from the left are the new tires.

But the second tire from the left is maybe just slightly smaller in diameter than the first tire. And the fifth tire from the left is larger than everything else. BUT the 2nd tire and the fifth tire seem to work perfectly. Is this an indication that the original tires were mismatche?
Left to right. Tires 1 and 3 are the old tires.

2 4 and 5 are new tires.

1&2 and 3&4 are stock sizes. 6-12, and 8-16. Stock sizes... Should work, but absolutely mis-matched based on rolling circumference. (Old tires are worse because the rears were heavily worn, and the fronts were only partly worn)

Tire 2 is smaller than tire 1, despite being the same size.

Tire 4 is larger than tire 3, partly due to tread depth, but also it is just larger diameter. But skinnier. Tire 3 is for an 8" rim, tire 4 is for a 6" rim.

Enter tire 5. a 9.5-16 that SHOULD NOT WORK according to everything I read on here. Well, doing the math out, with the Carlisle 6-12's, and it works. My driving around in 4x4 today also says it's working perfectly. Way better than the 13% lead I had with the old set of tires.


Tires 1 and 3 (old) had a 13.x% lead
Tires 2 and 4 had a 9.8% lead
Tires 2 and 5 have a 2.5% lead.
 

Henro

Well-known member

Equipment
B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
3,872
1,523
113
North of Pittsburgh PA
Left to right. Tires 1 and 3 are the old tires.

2 4 and 5 are new tires.

1&2 and 3&4 are stock sizes. 6-12, and 8-16. Stock sizes... Should work, but absolutely mis-matched based on rolling circumference. (Old tires are worse because the rears were heavily worn, and the fronts were only partly worn)

Tire 2 is smaller than tire 1, despite being the same size.

Tire 4 is larger than tire 3, partly due to tread depth, but also it is just larger diameter. But skinnier. Tire 3 is for an 8" rim, tire 4 is for a 6" rim.

Enter tire 5. a 9.5-16 that SHOULD NOT WORK according to everything I read on here. Well, doing the math out, with the Carlisle 6-12's, and it works. My driving around in 4x4 today also says it's working perfectly. Way better than the 13% lead I had with the old set of tires.


Tires 1 and 3 (old) had a 13.x% lead
Tires 2 and 4 had a 9.8% lead
Tires 2 and 5 have a 2.5% lead.
So it sounds like my assumption that things were wrong to begin with makes sense. 13% lead has to be excessive from what I have read. About 3% seems to be recommended. Sure sounds like you are where you should be now. (y)
 
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Lil Foot

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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
May 19, 2011
6,375
1,183
113
Peoria, AZ
Nice job, great persistence!
I also like those suitcase weights hanging on the box blade; if I ever find any weights, I will copy that from you!
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
Nice job, great persistence!
I also like those suitcase weights hanging on the box blade; if I ever find any weights, I will copy that from you!
dude those weights fell into my lap. 50+ lbs each and $75 for the pair. Made a huge difference in ballast with a full bucket. Still need to fill the new tires.

Haven’t drug anything with the new weights but I imagine it will massively help
 

Flintknapper

Well-known member

Equipment
L2350DT
May 3, 2022
346
408
63
Deep East Texas
So you ended up using the Carlisle Farm Specialist R1 9.5-16 on the rear?

Is that a tubeless tire? I am about to purchase rear tires for my L2350DT and I like that tread pattern.

But I don't want a tube tire and also want at least an 8 ply tire.

Just put CFS R1's on the front.

Front Tires4.jpg
 

PNW-Redleg

New member

Equipment
1978 B7100
Jul 3, 2022
25
8
3
Utopia of Portlandia
So you ended up using the Carlisle Farm Specialist R1 9.5-16 on the rear?

Is that a tubeless tire? I am about to purchase rear tires for my L2350DT and I like that tread pattern.

But I don't want a tube tire and also want at least an 8 ply tire.

Just put CFS R1's on the front.

View attachment 84102
Correct. check the Carlisle chart for the RC before you buy tho. Make sure you get something that will work properly.

you can run tubed or tubeless. I tried running tubeless but my rim was leaking so I had to put tubes in.